School-desk



(No Model.)

G. A. MASTERS. SCHOOL DESK.

No. 473,074. Patented Apr. 19, 1892.

r i J 2/ b n| d b Ir|| Z Mfu- WI w 7 V UNITED STATES PATENT OFFICE.

GEORGE A. MASTERS, OF CHICAGO, ILLINOIS.

SCHOOL-DESK.

SPECIFICATION forming part of Letters Patent No. 473,074, dated. April19, 1892.

Application filed April 13, 1891.

To all whom it may concern.-

Be it known that I, GEORGE A. MASTERS, of Chicago, in the State ofIllinois, have invented certain new and useful Improvements inSchool-Desks, of which the following is a specification.

My invention relates to adjustable schooldesks; and the object of myimprovements is to provide means for conveniently adjusting such desksto different heights in order to make them better subserve the purposesfor which they are designed. I have attained this object by the meansillustrated in the accompanying drawings, in which- Figure l is an endelevation of a schooldesk containing my invention. Fig. 2 is an enlargedfragmentary Vertical section taken on the line 2 2 of Fig. 1, lookingtoward the left, and representing a cross-section of a portion of one ofthe end frames and a longitudinal section of a portion of the shelf andtop of such desk. Fig. 3 is a detail showing a plan or top edge view ofa part of one of the end frames of such desk.

In the drawings, A designates the seat, A A the back pieces, B the top,and B the shelf, which are all of ordinary construction, and they areconnected to the end frames in the ordinary manner.

The means which I have provided for adjusting the desk to differentheights consists in making the end frames in separate sections at a andconnecting them by screw-rods b. There'are four of said screw-rodstwo ateach end of the desk. In the center said rods are each provided with anenlarged part b, fixed firmly thereto, so that said rods may be rotatedthereby with the hand or by means of a wrench applied thereto. Said rods.pass through openings 0 in the parts a a, which openings are eithermade oblong, as shown, or considerably larger than said rods, so as toafford sufficient play to avoid the binding of said rods or racking thedesk by any throwing of the parts out of square or normal position inthe operation of adjusting, as by raising or lowering the ends of thedesk separately. The parts a a" have transverse openings c in the lineof the openings 0, which are adapted to receive and hold each a nut e,which is put in place before the rod 1) is en- Serial No. 388,645. (Nomodel.)

tered, the transverse openings holding the nut from turning, so that therotation of the rod will cause the threads of the screwto operate andraise or lower the part a of the end frame. Said nuts 6 have asufficient vertical play in the openings 0 to be variable from theirhorizontal plane, in order to prevent any binding ofthe rods thereinduring the adjustin g of the desk for the reason before mentioned. Theparts of said rods opposite to the part b have their threads run inopposite directions, so that the rotationof said rods will cause thenuts 6 e thereon to move in 0pposite directions, in order to expeditethe operation of adjustment.

For the purpose of fixing the desk in any desired adjustment twojam-nuts e are provided on each of said rods, one to bear against thepart 66 and another to bearagainst the part a, whereby said rods may befixed rigidlyin said parts a a.

In the illustrations the desk is shown as set in its lowest adjustment.By turning the rods b to the right the jam-nuts will turn with the same,permitting the nuts 6 to move apart and elevate the top part d. Then theproper height is reached, the jam-nuts above the part I) should be setup against the part a, and the one below it down against the part a.

It is essential that the top part of the desk should be supported on atleast three points of supportthat is to say, there should be at leastthree of the rods b connected with the end frames, substantially in themanner shown, in order to properly support the top and permit it to beadjusted in the manner described; but four of said rods 1) arecontemplated, two in each of the end frames, as constituting the bestembodiment of my said invention.

The rods b as here shown are adapted to the minimum of standard heightof schooldesks and designed to permit of an elevation from that to themaximum standardQheight of the same.

Having thus described my invention, what I claim, and desire to secureby Letters Patcut, is

1. In a school-desk, and in combination, the end frames made in separatesections, as a a,

screw-rods b I), having swivel flexible connection with said sections,adapted to secure them to one another and allow fiection between them,and screw-thread connection adapted to adjust said sect-ions toward andfrom one another, and the parts I) Z) for revolving said rods,substantially as specified.

2. In a school-desk, and in combination, the end frames made in separatesections and provided with openings 0 and transverse openings c,intersecting each other, screw-rods fitting loosely in the openings 0,nuts e, fitting in said transverse openings and having slight verticalplay therein, and the parts I), fixed to said screw-rods, substantiallyas and for the purpose specified.

3. In a school-desk, and in combination, the end frames made in separatesections a a and provided with intersecting openings 0 c, rods I),having the parts 1) near their center and provided with threads runningin opposite direction on each side of said parts I), and nuts 6, inconnection with said rods and both of said sections a a, as and for thepurpose specified.

4. In a school-desk, and in combination, the end frames made in separatesections a 01., having intersecting openings 0 c, screw-rods I),provided with the parts 1) near the center and right and left handthreads at their 0pposite ends, screw-nuts c, and jam-nuts c, allconnected and adapted to operate as and for the purpose specified.

GEORGE A. MASTERS.

\Vitnesses:

WM. R. GRIsWoLn, J1-., ROBERT VAN SANDS.

